1. Field of the Invention
The present invention relates to a developer remaining amount detecting method, a developing device, a process cartridge and an electrophotographic image forming apparatus.
In the present specification, the process cartridge integrates charging means, developing means or cleaning means with an electrophotographic photosensitive member into a cartridge, and the cartridge is detachably mountable on an image forming apparatus main body. Also, the process cartridge integrates at least one of the charging means, the developing means and the cleaning means with the electrophotographic photosensitive member into a cartridge, and the cartridge is detachably mountable on the image forming apparatus main body. Further, the process cartridge integrates at least the developing means with the electrophotographic photosensitive member into a cartridge, and the cartridge is detachably mountable on the image forming apparatus main body.
Also, the developing device includes the developing means and a developer containing portion and develops an electrostatic latent image formed on the electrophotographic photosensitive member with a developer to visualize the image.
2. Related Background Art
Up to now, in an electrophotographic image forming apparatus using an electrophotographic image forming process, there has been applied a process-cartridge system, that is, the electrophotographic photosensitive member and process means that acts on the electrophotographic photosensitive member are integrated together into a cartridge, and the cartridge is detachably mountable on the image forming apparatus main body. According to the process cartridge system, since the maintenance of the apparatus can be conducted by a user per se instead of an attendant, the operability can be remarkably improved. For that reason, the process-cartridge system has been widely employed in the image forming apparatus.
In the above electrophotographic image forming apparatus, when the remaining amount of a developer (toner) contained in the developer containing portion of the developing means provided in the process cartridge is equal to or less than a predetermined amount, a user is notified of no toner and urged to exchange the process cartridge.
A conventional toner remaining amount detecting method of the light transmission type will be described with reference to FIG. 14. FIG. 14 is an explanatory diagram showing the toner remaining amount detecting structure of a developing device provided in a process cartridge.
In FIG. 14, reference numeral 104 denotes a developing device with a developer container 116 that contains toner T therein. An agitating member 112 is disposed within the developer container 116. The toner T is carried to a supply roller 111 with the rotation the agitating member 112. A lower light transmission window 114a and an upper light transmission window 114b for transmission of a light are fitted onto the developer container 116. The lower light transmission window 114a is disposed just below the rotating center of the agitating member 112, and the upper light transmission window 114b is disposed on a rear wall 116a. The lower light transmission window 114a and the upper light transmission window 114b form an optical path that transmits a detection light for detecting the remaining amount of developer. The agitating member 112 comes in contact with the lower light transmission window 114a and the upper light transmission window 114b every time the agitating member 112 rotates so as to wipe off the toner T stuck onto the inner sides of the respective light transmission windows 114a and 114b. 
Light transmission is performed in such a manner that detection light L is emitted from a light emitting portion 115a fitted on the image forming apparatus main body (not shown), and the detection light L is transmitted by the lower light transmission window 114a and then transmitted by the upper light transmission window 114b. Thereafter, the detection light L is received by a light receiving portion 115b fitted onto the image forming apparatus main body.
The toner T within the developer container 116 is increasingly consumed in proportion to the image forming operation of the electrophotographic image forming apparatus, thereby coming to a state where the toner T remains only in a region portion of the supply roller 111 and the rotation region of the agitating member 112. When the toner T is further consumed such that the amount of toner T in the rotation region of the agitating member 112 is so reduced as to be substantially empty, the light is transmitted from the lower light transmission window 114a toward the upper light transmission window 114b, resulting in a state where the remaining amount of toner T is detectable.
In that state, how long the detection light L is received by the light receiving portion 115b during one revolution of the agitating member 112 is monitored. In this case, because the amount of toner T in the rotation region of the agitating member 112 within the developer container 116 is reduced, a period of time during which the detection light L is received by the light receiving portion 115b increases. Then, when the light receiving portion 116b detects the detection light L for a specific light receiving period of time (a set light receiving period of time for detecting no toner), the user is notified of the fact that the toner becomes almost empty in the developer container 116.
In the above developing device, when the amount of toner in the rotation region of the agitating member within the developer container is so reduced as to be nearly empty, the lower light transmission window and the upper light transmission window start to transmit the detection light for detecting the remaining amount of toner. This is because the detection light transmitted through the lower light transmission window disposed below the rotating center of the agitating member is prevented from being blocked with the toner since the amount of toner in the rotation region of the agitating member is so reduced as to be nearly empty. Accordingly, at the time when the user is informed of no toner, the toner hardly exists within the developer container.
The invention further develops the aforementioned conventional art.
The prevent invention has been made to further improve the above related art, and therefore an object of the present invention is to provide a developer amount detecting method, a developing device, a process cartridge and an electrophotographic image forming apparatus which are capable of successively detecting the remaining amount of developer.
Another object of the present invention is to provide a developer remaining amount detecting method, a developing device, a process cartridge and an electrophotographic image forming apparatus which are capable of detecting the remaining amount of developer from a stage where the developer remains in the developer containing portion.
Still another object of the present invention is to provide a developer amount detecting method, a developing device, a process cartridge and an electrophotographic image forming apparatus which are capable of successively detecting the remaining amount of developer by using a variation in light amount.
Yet still another object of the present invention is to provide a developer amount detecting method, a developing device, a process cartridge and an electrophotographic image forming apparatus which are capable of successively detecting the remaining amount of developer on the basis of a period of time during which a light is blocked with the developer carried by a developer carrying member.
Yet still another object of the present invention is to provide a developer remaining amount detecting method, a developing device, a process cartridge and an electrophotographic image forming apparatus which are capable of successively detecting the remaining amount of developer on the basis of a period of time during which the light is blocked with a developer carried by a developer carrying member, in which the developer is carried to a position in which the developer blocks the light that has entered a developer containing portion from a first light transmission opening of a developer containing portion for containing the developer with the developer carrying member when the light transmitted to the interior of the developer containing portion from the first light transmission opening is transmitted to the exterior from a second light transmission opening of the developer containing portion.